Method dimDecrement

Core/VirtualQuantumProcessor/SingleAmplitude/Tensor.cpp:151–203

}

void CPUComplexTensor::dimDecrement(size_t num)
{
    if ((num > m_rank) || (m_rank == 0))
    {
        QCERR("dimDecrement error");
        throw std::runtime_error("dimDecrement error");
    }

    auto size = 1ull << m_rank;
    auto sub = m_rank - num;
    qsize_t step = 1ull << sub;
    m_rank = this->m_rank - 1;

    auto new_size = 1ull << m_rank;
    auto new_tensor = (qcomplex_data_t *)calloc(new_size, sizeof(qcomplex_data_t));
    if (nullptr == new_tensor)
    {
        QCERR("calloc_fail");
        throw calloc_fail();
    }

    size_t k = 0;
    size_t step_num = size / step;
    int threads = get_num_threads(m_rank);

    if (step_num <= 4)
    {
        for (long long i = 0; i < size; i += step * 2)
        {
            k = i / (2 * step);
#pragma omp parallel for num_threads(threads)
            for (long long j = i; j < i + step; j++)
            {
                new_tensor[j - k * step] = (m_tensor[j] + m_tensor[j + step]);
            }
        }
    }
    else
    {
#pragma omp parallel for num_threads(threads) private(k)
        for (long long i = 0; i < size; i += step * 2)
        {
            k = i / (2 * step);
            for (long long j = i; j < i + step; j++)
            {
                new_tensor[j - k * step] = (m_tensor[j] + m_tensor[j + step]);
            }
        }
    }

    free(m_tensor);
    m_tensor = new_tensor;
}


qcomplex_data_t *CPUComplexTensor::getTensor()